Executive Summary

To improve Mission Capable (MC) and Aircraft Availability (AA) rates, military aircraft require regular maintenance to ensure flight readiness. When aircraft are on the ground and/or in hangars, the signal between onboard radio systems and ground base stations can be subpar due to undesigned antenna angles as well as blockages by aircrafts’ hulls and/or hangar walls, therefore, causing difficulties for in-situ communication and maintenance. To support 5G/B5G aircraft maintenance and mission readiness use cases, the Joint Base Pearl Harbor-Hickam (JBPHH) 5G initiative is upgrading hangars to support 5G Ultra-Wideband (UW) communication. Typical base stations at these bands may leverage massive antenna arrays to form directional signal beams pointing line-of-sight (LoS) toward receivers, hence amplifying the receive signal strength (RSS) and improving the signal-to-noise ratio (SNR). However, such LoS communication links can have coverage gaps due to the aforementioned challenges. For example, aircraft can create 5G dead zones (e.g. shadowing) for LoS small cells in hangars. Thus, there is a need for beyond LoS signal propagation to increase 5G signal coverage in aircraft maintenance environments.

Naval Information Warfare Center Pacific (NIWC Pacific) will provide project oversight and support to the University of Hawaiʻi at Mānoa (UHM) to demonstrate improved 5G signal coverage using beam-steering Intelligent Reflecting Surfaces (IRS). Our approach to improve signal coverage uses the electrical actuation of liquid metal (LM) to modify signal reflection and thus reconfigure the gain and phase of an IRS to steer a 5G signal between a transmitter and receiver. In Year 1, we will demonstrate increased 5G band 78 (3.5 GHz) small-cell signal coverage with the proposed IRS and accompanying design control software and algorithms. We will also design an IRS for 5G band 260 (39 GHz). In an optional Year 2, we will demonstrate increased 5G band 260 small-cell coverage by creating an IRS optimized for mm-wave signals. We will also show that the IRS’s link-selection properties can enable multi-user multiple-input multiple-output (MU-MIMO) communication for concurrent data transmissions.